Automatic needle bar positioner



June 11, 1968 A clcco'rELLi JR 3,387,579

AUTOMATIC NEEDLE B'AR POSITIONER Filed Oct. 11, 1965 FIG m O l I m IL, o-/5 m H ll" m/vewron I 4 ANT/{0N7 A. C/CCOTE'LL/JR.

.AZ' FNEV United States Patent 3,387,579 AUTOh IATIC NEEDLE BARPGSITIONER Anthony A. (Iiccotelli, In, 505 Golf Ave, Oaklyn, NJ. 08107Filed Oct. 11, 1965, Ser. No. 494,655 Claims. (Cl. 112-221) ABSTRACT OFTHE DISCLOSURE An automatic needle bar positioner on a sewing machinehead having an aperture through the top with a needle drive barreciprocating therethrough between upper and lower stroke limitscomprising a sleeve afiixed in said aperture between said head and saidbar, said sleeve including an externally threaded portion extendingabove said top, a collar removably aifixed on said bar over said sleeve,a biasing means bearing against said collar and urging said bar in adirection parallel to reciprocation thereof, to position said her whilesaid sewing machine is at rest, at a stroke limit of said reciprocatingdrive bar upon cessation of said reciprocation, and a hollow elongatedtubular cap with an open internally threaded end engaging said threadedportion to enclose the upper end of said bar, collar and biasing means,said cap being readily unscrewed and said collar readily removed for aninterchange of said biasing means to alternate positions between saidcollar and sleeve and said collar and cap, respectively, therebyproviding a selective positioning of said bar to one of said strokelimits.

This invention relates in general to sewing machines, and in particular,to a device for stopping a reciprocating needle drive bar at a desiredposition.

The highly competitive garment industry employs skilled artisans tooperate sewing machines at a high rate of production. Naturally, sewingmachines with time saving features are very desirable. Contemporary highspeed sewing machines have a disadvantage in that the needle is oftenout of position upon stoppage of the machine. That is, the needle is ata position other than the up or down stroke limit, requiring a manualpositioning of the needle for removal of the work piece or a change institch direction. A great deal of time may be saved by my inexpensiveinvention which adapts existing sewing machines for an automaticpositioning of the needle at an up or down stroke limit.

Therefore, to overcome the foregoing and other difficulties of the priorart, it is the general object of this invention to provide a device forexisting sewing machines which automatically positions a needle uponstoppage of the machine.

It is an object of this invention to provide an automatic needle barpositioner which is adaptable to position a needle at an up or downstroke limit, as desired.

Another object of this invention is to provide an automatic needle barpositioner which is economic and simple in operation, requiring aminimum of maintenance.

A further object of this invention is to provide an automatic needle barpositioner which is economical to pro- 3,387,579 Patented June 11, 1968duce by utilizing conventional, currently available standard componentsthat lend themselves to standard mass production manufacturingtechniques.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawing, in which:

FIGURE 1 represents an end elevation of a sewing machine and automaticneedle bar positioner in cross section;

FIGURE 2 is an exploded perspective view of an automatic needle barpositioner;

FIGURE 3 is a partial end elevational view similar to FIGURE 1illustrating an alternate adaption of the invented device; and

FIGURE 4 is a perspective view showing a rotating shuttle hook, modifiedin accordance with the present invention. 7

Referring to the drawings in detail, wherein like numerals indicate likeelements, there is shown in FIGURE 1 a drawing of a sewing machineindicated generally by the numeral 10. The machine It) may be a standardindustrial sewing machine having a hand wheel 12, a head 13 (insection), a needle drive bar 14, a needle 15, a pressure foot 16, and arotary shuttle hook 18. A conventional drive to reciprocate the drivebar 14 through apertures at the top and bottom of head 13 is provided bya rotary shaft 19 which is connected to bar 14 through the standardcrank linkages shown in FIGURE 1.

Normally, the apertures at the top and bottom of head 13, through whichdrive bar 14 extends and reciprocates are lined by bushings, such asthat illustrated at 17. The invented device is utilized for adaption ofexisting machinery, therefore, a replacement sleeve 20 is included as asubstitute for the bushing originally at the top of head 13. The sleeve29 has an enlarged externally threaded end portion 22, which extendsabove the top of head 13 when the sleeve is inserted in place, asindicated. A set screw 21, provided for the original bushing, firmlyaffixes the sleeve 20 in place within the aperture in head 13.

A removable collar 25 fits on a portion of bar 14 extending above thesleeve 2!). Set screw 27 may be tightened to affix the collar 25 at-adesired position on bar 14. A biasing means is provided by the helicalcoil compression spring 30, which fits around the bar 14 with one endhearing against collar 25.

The bar 14, sleeve 29, collar 25 and spring 3% are enclosed by a hollowelongated cap 35, as illustrated. Sufficient clearance is providedbetween the inside surfaces of the cap 35, the collar 2% and the upperstroke limit of bar 14, to enable unhindered reciprocation therein. Theopen end of cap 35 is internally threaded, as indicated, for engagementwith the externally threaded portion 22 of sleeve 20. The opposite,enclosed end of cap 35 provides a bearing surface at 37 for the spring30 in the alternate adaption of FIGURE 3. A slot 36 may be provided tofacilitate the placement and removal of the cap 35 by means of a toolsuch as a screw river. It is understood, of course, that other wellknown means may be employed for a quick and convenient placement orremoval of the cap 35. For example, a square or hexagonal shape togetherwith an appropriate wrench, or knurled surfaces for the fingers may beprovided for unscrewing the cap 35.

In some instances, the original drive bar of the sewing machine may notextend a sufiicient distance above the threaded end 22 of sleeve 26 toaccommodate the collar 25 and the spring 30. In such cases it will benecessary to provide an elongated replacement bar 14. For universalapplication, on all sizes of machines, it is proposed that thereplacement for drive bar 14 have a hollow axial bore, internallythreaded at one end 53 to receive threaded stud portions of barextension sections (not shown). Thus, an appropriate replacement lengthmay be accomplished by merely adding the proper size of replacementsection. Otherwise, a machine screw 50 may be screwed into bore 5'3 tocap the replacement bar 14 as shown.

The operation of sewing machines utilizing the invented automatic needlebar positioner device may be controlled by a conventional sewing machinetransmitter, which is operated by a foot pedal or the like. Sewingmachine transmitters are well known in the art, serving to controlmotive power to the machine by alternate engagement between a clutch anda brake. Since the transmitter is conventional and forms no part of thepresent invention, no further description is necessary. However, forbest operation of the invented device it is desirable that thetransmitter be adjusted, in a manner familiar to those skilled in theuse of sewing machines, to provide a neutral position; that is, with theclutch and brake both disengaged. For example, the transmitteradjustment may be such that pressure to the front of the foot pedal bythe toe, or to the back of the pedal by the heel, will engage the clutchand brake, respectively, but removal of all pressure from the pedal willfree the needle bar mechanism from engagement with either clutch orbrake.

If it is desired to stop the machine with the needle at an upper strokelimit, the invented device must be adapted on the sewing machine asillustrated in FIGURE 1. The spring 30 is positioned around bar 14between the end portion 22 of sleeve and the collar 25. Thus, a downwardreciprocation of the drive bar 14 will compress the spring 30 to causean upward biasing force between the sleeve 28 and the collar 25. Aproper adjustment of collar 2.5 by means of set screw 27 will insure asuficient compression of spring 30 to bias the drive bar 14 to an upperstroke limit, as shown, whenever the transmitter foot pedal is at aneutral position. Since the needle bar mechanism is free from engagementwith either the clutch or brake, the bias of spring 30 will cause theneedle 15 to stop at the upper stroke limit. It is understood, that thetension of spring 30 be sufiicient to motivate the needle bar mechanismwhen free, however, insufiicient to interfere with the operation of themachine whenever the clutch or brake are adequately engaged.

FIGURE 3 shows the invention adapted to position the needle at thedownward stroke limit. This may be quickly and easily accomplished fromthe adaption shown in FIGURE 1 by unscrewing cap 35 and set screw 27 toremove collar and spring 30. The collar and spring are quickly replacedin reverse positions, with the spring around the bar 14 and above thecollar 25, as indicated in FIGURE 3. The collar 25 is positioned at apoint on bar 14 above end portion 22 of sleeve 2%} whenever the bar 14is at the downward stroke limit. The collar 25 is afiixed in position onthe bar 14 by tightening set screw 27. The cap is replaced on thethreaded end portion 22 to enclose the upper end of bar 14, collar 25and the spring 30 with one end of the spring 30 hearing against surface37 of the cap 35. An upward reciprocation of the drive bar 14 willcompress the spring 30 and cause a downward biasing force between thecollar 25 and the surface 37 of cap 35. Thus, whenever the transmitterfoot pedal is at a neutral position, the compression of spring 30 willbias the drive bar 14 to a downward stroke limit.

A partial reverse rotation of the drive bar mechanism may occur duringoperation of either of the adaptions, described above, of the inventeddevice. Some of the 4 standard rotary shuttle hooks are designed forrotation in a single direction and do not provide for a reverserotation. That is, certain projections and notches on the rotary shuttlehook would snag and break the bobbin thread upon a reverse rotation.FIGURE 4 illustrates a standard rotary shuttle hook 18 which has beenmodified to provide for a reverse rotation. During the sewing operation,the rotary hook 18 rotates in the direction indicated by the arrow,around the bobbin 51. The bobbin 51 is secured in hook 18 by adetachment arm 54, which includes a fingernail tab 55 for convenience inremoving the bobbin. The tab 55 allows the passage of thread in thedirection of the arrow, however, also provides an interfering projectionfor any passage in a reverse direction. Therefore the tab 55 must beremoved or bent inward as illustrated to provide a cambered surfacepermitting passage of thread in a reverse direction. Additionally, thestandard hook 18 may also have a notch (shown in phantom) for passage ofthe needle, which notch serves as a hook to snag thread upon reverserotation. The notch may be filled by soldering or brazing to form acambered edge 56 which will allow a reverse rotation without snagging ofthread. Naturally, it necessary, the timing of the needle may be delayedslightly by an adjustment well known in the art. Furthermore, theshuttle hook 18 may be manufactured as described above to eliminate needfor any modification.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof, andaccordingly, reference should be made to the appended claims, ratherthan to the foregoing specification as indicating the scope of theinvention.

What is claimed is:

1. On a sewing machine head having an aperture through the top with aneedle drive bar reciprocating therethrough between upper and lowerstroke limits, an automatic positioner for said bar, comprising: asleeve aflixed in said aperture between said head and said bar, saidsleeve including an externally threaded portion extending above saidtop; a collar removably aflixed on said bar over said sleeve; a biasingmeans bearing against said collar and urging said bar in a directionparallel to reciprocation thereof, to position said bar, while saidsewing machine is at rest, at a stroke limit of said reciprocating drivebar upon cessation of said reciprocation; and a hollow elongated tubularcap with an open internally threaded and engaging said threaded portionto enclose the up per end of said bar, collar and biasing means, saidcap being readily unscrewed and said collar readily removed for aninterchange of said biasing means to alternate positions between saidcollar and sleeve and said collar and cap, respectively, therebyproviding a selective positioning of said bar to one of said strokelimits.

2. An automatic positioner according to claim 1 wherein said biasingmeans is a helical coil compression spring around said bar.

3. An automatic positioner in accordance with claim 2 in combinationwith a rotating shuttle hook having cambered edges and surfaces allowinga reverse rotation thereof without snagging and breaking of threadthereon.

4. On a sewing machine head having an aperture through the top with aneedle drive bar reciprocating between upper and lower stroke limits, anautomatic needle bar positioner, comprising: an elongated replacementbar in place of said drive bar to provide a drive bar extension abovesaid top; a sleeve afiixed in said aperture between said head and saidreplacement bar, said sleeve including an externally threaded portionextending above said top; a removable collar on said drive barextension; a set screw extending radially inward through said collar toprovide a selective removal and positioning of said collar on said barextension; a helical coil compression spring around said bar extension,said spring having an end against said collar to urge said replacementbar in a direction parallel to reciprocation thereof and position saidreplacement bar, while said sewing machine is at rest,

at a stroke limit of said reciprocating replacement bar upon cessationof said reciprocation; and a hollow elungated tubular cap with an openinternally threaded end engaging said threaded portion of said sleeve toenclose the upper end of said bar extension, collar and spring, said capbeing readily removable for an interchange of said spring to alternatepositions between said collar and sleeve and said collar and cap,respectively, thereby providing a selective positioning of saidreplacement bar to one of said stroke limits.

5. An automatic positioner in accordance with claim 4 in combinationwith a rotating shuttle hook having cambered edges and surfaces allowinga reverse rotation thereof without snagging and breaking of threadthereon.

References Cited UNITED STATES PATENTS 347,089 8/1886 Carr 112-218386,837 7/1888 Litchfield. 2,009,194 7/1935 Hleb 112239 2,176,95710/1939 Covell 1l2-79 2,218,123 10/1940 Smith 112221 X FOREIGN PATENTS90,440 12/ 1922 Austria.

JORDAN FRANKLIN, Primary Examiner.

H. H. HUNTER, Examiner.

